“…In the absence of visible light or under white light irradiation, no desired product 3 aa was observed (Table 1, entries 16 and 17). Subsequently, several photocatalysts, including Ru(bpy) 2 Cl 2 , methylene blue, fluorescein, rose bengal and eosin Y, were examined to improve the efficiency of the [c] 390-395 nm CH 3 CN -82 26 [d] 390-395 nm CH 3 CN -Trace 27 [e] 390-395 nm CH 3 CN -71 28 [f] 390-395 nm CH 3 CN -84 29 [g] 390-395 nm CH 3 CN -73 30 [h] 390 Cl 2 ) = 0.77 V versus SCE in acetonitrile, [26] E p/2 (methylene blue) = 1.60 V versus SCE in acetonitrile, [27] E p/2 (fluorescein) = 0.78 V versus SCE in acetonitrile, [28] E p/2 (rose bengal) = 0.99 V versus SCE in acetonitrile, [29] E p/2 (eosin Y) = 0.79 V versus SCE in acetonitrile]. [30] So, the above mentioned photocatalysts cannot react with substrate 1 a (E p/2 = 1.84 V versus SCE in acetonitrile) or 2 a (E p/2 = 1.81 V versus SCE in acetonitrile) via an electron transfer process.…”